20.8
Barium has a charge of -2 and Oxygen has a charge of +2. Oxygen is nature appears as O2, therefore Barium + Oxygen = barium oxide; Ba + O2 = BaO; 2Ba + O2 = 2BaO
The product will be Barium Oxide and as Barium has 2 valence electrons and oxygen needs 2 to get to a stable octet, the formual must be BaO. You have O2 and thus must need 2 Ba to balance. So 2Ba + O2 ------> 2BaO
The formuls of the compound barium nitrate is Ba(NO3)2. The question as stated has no unique answer, because many other compounds can be formed from barium nitrate, depending on what else is available to react with the barium nitrate.
Barium peroxide (BaO) decomposes in water to barium oxide and oxygen. Barium oxide will further react with water to produce barium hydroxide. Summing up: 2BaO+2H2O-->2Ba(OH)2+02
Aluminium oxide is an amphoteric substance, meaning it can react with both acids and bases, such as hydrochloric acid and sodium hydroxide, acting as an acid with a base and a base with an acid, neutralising the other and producing a salt.